About two years ago, I tried FF8 and Chrono Cross with many different video plugins, and they all looked warped. I was using a GF6600GT at the time. I tried ePSXE or whatever that was, and several others that supported the same plugin type (AdriPSX, etc). I tried FF7, and the 2d graphics looked awful. The games were designed to output at probably 320x240, maybe 640x480.
Then again, I personally never liked the way PSX handled 3D. To me, the wavy textures and the somewhat abnormal polygon movement REALLY bugged me. I only own a handful of fully 3D games for PSX, as I mainly bought one for Megaman. The 3D rendering winner of that era was N64, but the lack of texture storage space somewhat hindered it.